Moisture tester



Oct. 17, 1961 E. E. BERKLEY ETAL 3,005,153

MOISTURE TESTER 2 Sheets-Sheet 1 Filed May 26, 1958 Oct. 17, 1961 E. E. BERKLEY ETAL 3,005,153

` MOISTURE TESTER Filed May 26, 1958 2 sheets-sheet 2 INVENTOR5 3,005,153 MOISTURE TESTER Earl E. Berkley and .lohn A. Roddick, both of Box 2538, Houston, Tex. Filed May 26, 1958, Ser. No, 737,744 4 Claims. (Cl. 324-65) This invention relates to an apparatus for determining the percentage moisture content of brous material and more particularly relates to au apparatus for determining such moisture content by measuring the electrical direct current resistance to the brous material and relating it to the percentage moisture. This application is a continuation-in-part to our application for a Moisture Tester, Serial No. 651,473, tiled April 8, 1957.

The moisture content of brous materials such as ginned cotton or seed cotton is important in many instances. For example, cotton is traded on a weight basis and therefore its moisture content needs to be known and controlled. Also, the moisture content of cotton aifects both the ginning procedure and results. Furthermore a high moisture content in the cotton seed in seed cotton will cause a free fatty acid rise and a subsequent high reiining loss in cotton seed oil.

It is old in the art to compress the sample of cotton or other ber, determine the electrical direct current resistance of the fiber so compressed and compare this resistance with a curve plotting direct current electrical resistance against percentage moisture content to determine the percentage of moisture in the sample. The devices in use now have several objectional features with the principal one being the amount of time required for making a test. The reduction of the time necessary to conduct a test reduces the labor costs and in many instances gives more accurate results because the liber sample Will change its moisture content by the time the test is completed because of the length of time required to conduct the test.

It is therefore a general object of the present invention to provide an apparatus for quickly determining the moisture content of brous material.

Another object of the present invention is to provide an apparatus for determining moisture content of such material in which the apparatus utilizes a direct current electrical resistance meter to indicate directly the percentage moisture content of the sample being tested.

A further object is to provide such a moisture testing apparatus in which the test sample may be placed under controlled pressure.

Yet a further object of the present invention is to pro vide such an apparatus which utilizes a vertical testchamber with a self opening tilting plunger plate so that the loading, unloading and cleaning of the test chamber is smplilied.

A still further object of the present invention is to pro vide such an apparatus which is easily portable and yet has a test chamber of sufficient size to test a representative sample.

A still further object of the present invention is to provide such an apparatus which is rugged, easy to use, inexpensive and economical to maintain. l

Other and further objects, features, and advantages of the present invention will appear as a description of the preferred example or" the invention proceeds, which is given for the purpose of disclosure and which is taken in conjunction with the accompanying drawings, where like character references designate like parts throughout the several views and where,

FIGURE 1 is a schematic drawing of the present invention illustrating the fluid pressure system, spring return and electrical circuits,

Patented Oct. l?, i961 FIGURE 2 is a front elevational view of the moisture tester of the present invention,

FIGURE 3 is a cross-sectional view taken along the line 3--3 of FIGURE 2 and illustrating the test chamber in the open position,

FIGURE 4 is a view similar to FIGURE Il illustrating the present invention with the test chamber in the closed and testing position,

FIGURE 5 is an enlarged sectional View of one corner of the test chamber illustrating its construction and the electrical connection,

FIGURE 6 is an enlarged sectional View of the electrical connection to the plunger plate, and

FIGURE 7 is an enlarged exploded perspective view of the plunger plate return spring assembly.

Referring to the drawings, and particularly to FIGURE 2, the moisture tester as a whole includes a test chamber lil in which a fibrous sample is compressed by hydraulic system indicated generally by the numeral l2 during which time the direct current electrical resistance of the compressed sample is indicated by a resistance meter 14.

As best seen in FIGURES 2, 3 and 4, the test chamber l@ is preferably cylindrical in shape and its outer case 16 is made of aluminum to give a light Weight but sturdy construction. At the bottom end of the test chamber l() as viewed in FIGURES 3, 4 and 5, is a fixed circular electrode plate l of electrically conductive material, prefer-Y ably copper, which plate 18 is electrically insulated from the outer case le by the liner Ztl of transparent acrylic plastic known as Plexiglas or other insulating material.`

The electrode plate 15 may be held in position by a force fit in the liner 2i). As thus constructed the xed plate 18 is electrically insulated from the test chamber lll except for its exposed inner face.

The top of the test chamber lll is open and an opening 22 is provided in a portion of the top of the side Wall of the test chamber lll for inserting into and removing a sample from and for cleaning the test chamber 10. In

the top opening of the test chamber lil an electrically con-- Referring to FIGURE 2, there is shown a test stand assembly including a base plate 3% which, if desired, may be extended to provide a single base for both the test stand assembly and the electrical resistance meter 14. Support rods 40 are connected to the base plate 3S and to a top plate Sil. A movable plate 42 between the top plate 3l) and the base plate 3S is provided with openings 44 through which the support rods 4@ slidably extend so that the plate 42 is guided by the supports d0 as it is moved up and down. The test chamber lil is secured to the movable plate 42 by any desired means such as screws (not shown). A piston rod 56 in the hydraulic system l2 is secured to the lower side of the plate 42 and provides the means for moving the plate (i2 and the test chamber 16 upwardly relative to the plunger plate 24 l so as to close the test chamber and compress a sample therein. Return springs 46 are provided on the support rods 40 between the movable plate 42 and the top plate 3 vided on the top plate 3u for carrying the entire assembly and ease of handling.

Referring now to FIGURES l, 2 and 3 there is best illustrated the iiuid pressure system, here shown as the hydraulic system l2 which advances the movable plate 42 and the test chamber 16 toward the plunger plate 24 for compressing the test sample. This hydraulic system includes the pump control unit Sil which may be of any of several commercial assemblies and which units are readily available on the market. in the preferred example a Simplex hydraulic jack manufactured by Templeton, Kenly and Company, Broadview, ll'l. is quite satisfactory. The pump control unit 5t) includes a pivoted pump handle 52 as the means to develop the amount of lluid force in the cylinder 5l required for raising the piston 54 and piston rod 56 and thereby raising the movable plate 4.12 and the test chamber l0. A relief valve 58 is provided for releasing the hydraulic pressure from the pump thereby allowing the springs 46 to return the movable plate 42 to its lowered position. Also a pressure gauge dil is provided on the pump control unit Si? to indicate the pressure exerted by the hydraulic system 12 on the sample in the test chamber lill.

Referring now to FlGURES 3, 4 and 7, the plunger plate 24 is pivotally mounted on pin 26 which is supported by hinge bracket 28 attached to the top plate Eil. As best seen in FIGURE 7, the plunger plate 24 is normally held in a horizontal position by a return spring 32 which provides `the force to return and yieldingly urge the plunger plate 2a parallel to the fixed plate A tilting plate trip 34 is attached to the top of the test chamber l@ in any conventional manner such as by screws 3d. This trip 34 is adapted to engage the back edge of the plunger plate 24 as the test chamber itl' is lowered thereby causing the plate 24 to incline opening at the sidewall opening 22 thus making the opening to the test chamber larger and more accessible to loading and unloading without increasing the diameter of the test chamber ld.

Referring now to FIGURES l and 2, the electrical circuit to measure the direct current resistance of the brous sample compressed between plates 2d and 18 includesthe resistance meter 14 connected to a 110` volt AC. supply. The meter l@ is connected in series with the xed plate iii tls-rough a lead 62 from one terminal post of the resistance meter ld and to the tilting plunger plate 24 through a lead ed connected at one end to another terminal post on the resistance meter ld. The resistance meter le converts the alternating current supply to a direct current flow through the test sample. The resistance meter may be of any several standard types commercially available on the market such as SLE., model C-6 resistance meter manufactured by Southwestern Industrial Electronics Company, Post Office Box 13085, Houston i9, Tex.

In FIGURES 5 and 6, is illustrated the connection of the electrical leads 62 and tid, respectively, from the meter le to the electrical pilates li and 24. Referring to FIGURE 5, an electrical terminal connection plug 6e is attached to the iixed copper plate 18 and has a ush tapered head and a bottom section threaded for a hexagon nut 67 which secures the plug de in place. An insulated opening 68 is provided in the casing lo so that a conventional banana plug connection 70 may be made at the bottom of the terminal connection plug d6. The electrical lead 62 is preferably a shielded type cable with the shield being grounded to the test chamber lil through the ground screw '72. Similarly, referring to FIGURE 6, an electrical terminal connection plug 74 is provided in the plunger plate 24- so that a conventional banana plug connection 72 to the lead 64 is made by the plunger plate Z4.

As thus connected the resistance meter 14 will measure the resistance to electrical flow between the plates 1S and 24 and of the sample compressed therebetween. In order that the resistance meter 14 will indicate directly the percentage of moisture of the sample being tested rather than its electrical resistance, as best seen in FIG- URE 2, a face plate 76 is inserted on the resistance meter ltd which reads directly in moisture percentage rather than in ohms electrical resistance. This face plate 76 is prepared from a curve of the electrical direct current resistance of the material being tested pllottcd against the known moisture percentage content of the material. ln the case of testing cotton the known moisture content is preferably determined by determining the weight difference of the tested sample before 4and after heating it for an hour and a half in an oven at 1105 to 119 degrees centigrade. As most resistance meters utilize a selector knob such as the knob 78 to change the resistance range indicated by the meter for the variances of moisture content encountered in the test samples, the face plate 76 utilizes a se-ries of calibration arcs i9 with one being for each resistance range put in operation by the selector knob 7S.

In operation, the l1() volt AC. supply is turned on to the resistance meter i4 by a toggle switch Si? (FlJURE 2) to allow the resistance meter le to come `to operating condition. A sample of the material is then inserted into the top opening 22 and under the tilted plunger plate 24 into the test chamber lll between the plates 2A and 18, then in the position illustrated in FIGURE 3. The relief valve 58 of the pump control unit 50 is closed and pressure is applied to the bottom side of the pistou 54 by operating the pump handle 52 until pressure on thepressure gauge .titl reaches the desired reading for pressure in the test chamber l0. The pump piston Se and piston rod 56 raise the movable plate 42 and move the test chamber lil toward the pivotally mounted plate 24. As the test chamber 10 moves upwardly the trip 34 Which has been holding the plate 24` in a tilted or open position releases the plunger plate 2d and the return spring 32 causes the plunger plate 24 to return to the horizontal position causing compression of the sample as shown in FIGURE 4. By proper manipulation of the selector lmob 73 to the proper range the needle "i7 will show the percentage of moisture content of the material at the time the pressure in the test chamber lil reaches the desired point indicated by the pressure gauge 6l). After the test is complete, the relief valve 58 is opened thereby releasing the hydraulic pressure of the system and the return springs lo move the movable plate 42 and test chamber itl downwardly to their starting position. As the test chamber l0 moves downwardly the trip 34 catches the edge of the plunger plate 24E- and pivots it around the pin 26 tilting the plunger plate 24 upwardly and opening the top of the test chamber l@ allowing easy accessibility for removing the sample as illustrated in FIGURE 3. Then another sample may be inserted and the cycle quickly repeated thus providing an apparatus which quickly measn ures the moisture content of a sample of cotton.

During the entire period of testing the resistance meter 14 is supplied with alternating current which is converted to direct current and supplied to the plates 18 and 24 without the necessity of this electrical circuit to the plates 18 and 2d being turned on or oil so that the moisture content is indicated directly and instantaneously upon reaching the desired pressure.

As the direct current electrical resistance of the samples depend upon, among other things, the distance between the plates 13 and 2dand the amount of pressure on the sample, the size of the samples on the pressure are preferably comparatively uniform for the test conducted. For example, with seed cotton samples weighing to grams are normally tested and lint cotton samples of 33 to 37 grams are normally used. For each of these cottons it has been found that pressures inthe test chamber in excess of 40 pounds per square inch give the most reliable results.

For purposes of illustration the structure and operation have been described with the test chamber A10 in a vertical position but of course the apparatus can be used in any position. However, in some instances of high moisture content it has been found that the Vertical operation gives more accurate results because of amount of moisture freed by the compression of the sample.

The present invention, therefore, is well suited to carry out the objects and attain the advantages mentioned herein as well as others inherent therein. While only a single example of the invention has been given for the purposes of illustration, changes in details and rearrangements of parts will readily suggest themselves to those skilled in the art. Accordingly, it is desired to be limited only by the spirit of the invention as defined by the scope of the appended claims.

What is claimed is:

1. In a moisture tester having a test chamber adapted to hold a sample of material, said chamber including an opening at one end for inserting and removing a sample, iirst and second electrically conductive plates associated with the test chamber, means electrically insulating the plates from each other through the chamber, means advancing the electrical plates towards each other whereby a sample between the plates is compressed, control means controlling the force of compression on the sample, means retracting the electrical plates from each other thereby releasing the sample between the plates, the improvement comprising the tirst electrically conductive plate being pivotally mounted proximate the opening in the test chamber, means yieldingly urging said irst plate parallel to the second plate, and means associated with the iirst plate adapted to tilt said iirst plate as the electrical plates are retracted from each other thereby opening the test chamber.

2. 'Ihe improvement of claim 1 wherein the means retracting the electrical plates liront each other includes spring means whereby on release of the compression on the sample the plates are retracted from each other and the lirst plate is tilted thereby opening the test chamber.

3. In a moisture tester having a test chamber adapted to hold a sample of material, said chamber including an opening at one end for inserting and removing a sample, rst and second electrically conductive plates associated with the test chamber, means electrically insulating the plates from each other through the chamber, hydraulic means advancing the electrical plates towards each other whereby a sample between the plates is compressed, control means controlling the force of compression on the sample, means retracting the electrical plates from each other thereby releasing the sample between the chamber, and an electrical resistance meter connected to said rst and second conductive plates, the improvement comprising, the rst electrically conductive plate being pivotally mounted proximate the opening in the test chamber, stop means positioned adjacent said rst plate and on one side of the pivot limiting the movement of the plate about said pivot to a position parallel to said second plate, spring means acting against the first plate on a second side of the pivot yieldably urging said iirst plate against said stop thereby urging said first plate parallel to the second plate, and trip means connected to the said chamber adapted to engage and tilt said first plate about the pivot as the electrical plates are retracted from each other thereby opening the test chamber.

4. In a moisture tester having a vertical test chamber adapted to hold a sample of material, said test chamber including an opening at the top and in the side wall of the top for inserting and removing a sample, a first electrically conductive plate spaced in said top opening in the test chamber, said rst plate adapted to move relative to the test chamber into and out of the test chamber, a second electrically conductive plate secured near the second end of the test chamber, uid pressure means advancing the test chamber and the rst electrically conductive plate towards each other thus moving the rst and second plates toward. each other whereby a sample between the plates is compressed, means electrically insulating the plates from each other through the chamber, means moving the test chamber and the second electrically conductive plate away :from the iirst plate thereby releasing the sample between the chambers, and a direct current electrical resistance meter connected to said rst and second plates measuring the electrical resistance of the compressed sample, the improvement comprising, said irst electrical. conductive plate being pivotally mounted, stop means adjacent said pivot and on the side of the tirst plate remote from the second plate and positioned so that the rst plate is aligned parallel to the second plate when the rst plate contacts said stop means, spring means contacting the side of the rst plate remote from the second plate on a second side of the pivot yieldably urging said iirst plate parallel to the second plate, and a trip attached to the test chamber and positioned on the side of the rst plate remote from the second plate thereby tripping the irst plate as the test chamber moves away from the rst plate thereby opening the test chamber.

References Cited in the ile of this patent UNITED STATES PATENTS 47,490 Davies Apr. 25, 1865 837,652 Wilder Dec. 4, 1906 1,646,355 Hill Oct. 18, 1927 1,778,941 Hansen Oct. 21, 1930 1,826,247 Heppenstall Oct. 6, 1931 1,890,545 Limbriok Dec. 13, 1932 2,082,364 Store June 1, 1937 2,343,340 Stevens Mar. 7, 1944 2,469,736 McBrayer May 10, 1949 

